During a shift, you lift off throttle, thereby making the ECU drop the requested boost to nil, opening the wastegate, and causing the DV to operate (at least I think that's how it works), so, even if you were to pump the pressurized air through the SAI port, it would just go around the turbine, rather than spooling. Novel idea, but I don't think this is something that should be really pursued. Not to mention that port is quite small in relation to an actual turbo housing, etc...